The Twin Paradox Made Simple

[pzkpfw]

Of course that's not a paradox at all.  And that's also not the reason it's called a paradox.

 

Two people can have totally opposite "perceptions"  Nothing paradoxical about that at all.  It happens every day.  People make mistakes.

 

The "paradox" comes when SR tries to simultaneously claim that:

 

1.  There is no mistake at all.  Both are correct, but that

2.  Only one of the two twins is correct.

 

That's the "paradox," which SR "resolves" only by repudiating the first claim and affirming the second--which gives an absolute (frame independent) answer, not a relative one.

 

You continue to misrepresent the twins' paradox.

 

While two observers are in relative motion, for both of them, the others' clocks is slow (while for both of them their own clock is perfectly normal). They must be, for the speed of light to be invariant.

 

(I know you don't like this - you think it's contradictory and illogical - but that's your own flawed interpretation, not standard well known science.)

 

That reciprocal experience is what gives rise to the "paradox" in the "twins' paradox". In a scenario where A "stays home" and B zooms away from A then comes back to A, a learner can think "since at all times that they are in relative motion, the other's clock is always slower, how come B comes back and is actually younger"?

 

The answer is that the situation is not symmetrical. Observer A's clock stays in the same inertial frame the whole time, the B observer is "in" two frames, one moving away from A and then towards A. The experience of A and B is not the same.

 

(It should be noted that speed is relative, but acceleration is absolute. We can actually "prove" that it's A who stayed home and B who "changed" frames. Just give them both a cup of coffee at the start of the experiment. It's B who spills their coffee, not A. But note it's not the acceleration that itself "causes" the difference in age of the twins, experiments can be designed with observers who don't change their own inertial frame but who pass clock readings to each other, and the same basic result arises. That can make it easier to understand, e.g. https://www.scienceforums.net/topic/104573-the-twin-paradox-and-other-variants/?do=findComment&comment=981200 )

 

 

[ To be fair, I'll point out I'm not going to engage in your gish gallop. This post is here for the person who stumbles on this thread in the mainstream science section of the forum. They need to know your views are not science. ]

Edited May 3, 2018 by pzkpfw

[exchemist]

You continue to misrepresent the twins' paradox.

 

While two observers are in relative motion, for both of them, the others' clocks is slow (while for both of them their own clock is perfectly normal). They must be, for the speed of light to be invariant.

 

(I know you don't like this - you think it's contradictory and illogical - but that's your own flawed interpretation, not standard well known science.)

 

That reciprocal experience is what gives rise to the "paradox" in the "twins' paradox". In a scenario where A "stays home" and B zooms away from A then comes back to A, a learner can think "since at all times that they are in relative motion, the other's clock is always slower, how come B comes back and is actually younger"?

 

The answer is that the situation is not symmetrical. Observer A's clock stays in the same inertial frame the whole time, the B observer is "in" two frames, one moving away from A and then towards A. The experience of A and B is not the same.

 

(It should be noted that speed is relative, but acceleration is absolute. We can actually "prove" that it's A who stayed home and B who "changed" frames. Just give them both a cup of coffee at the start of the experiment. It's B who spills their coffee, not A. But note it's not the acceleration that itself "causes" the difference in age of the twins, experiments can be designed with observers who don't change their own inertial frame but who pass clock readings to each other, and the same basic result arises. That can make it easier to understand, e.g. https://www.scienceforums.net/topic/104573-the-twin-paradox-and-other-variants/?do=findComment&comment=981200 )

 

 

[ To be fair, I'll point out I'm not going to engage in your gish gallop. This post is here for the person who stumbles on this thread in the mainstream science section of the forum. They need to know your views are not science. ]

Thanks for injecting some science. 

 

What people often seem to overlook is that the time dilation seen by observers in relative motion is balanced by length contraction, such that c can be the same for both observers, their relative motion notwithstanding. 

[Moronium]

You continue to misrepresent the twins' paradox.

 

While two observers are in relative motion, for both of them, the others' clocks is slow (while for both of them their own clock is perfectly normal). They must be, for the speed of light to be invariant.

 

(I know you don't like this - you think it's contradictory and illogical - but that's your own flawed interpretation, not standard well known science.)

 

That reciprocal experience is what gives rise to the "paradox" in the "twins' paradox". In a scenario where A "stays home" and B zooms away from A then comes back to A, a learner can think "since at all times that they are in relative motion, the other's clock is always slower, how come B comes back and is actually younger"?

 

The answer is that the situation is not symmetrical. Observer A's clock stays in the same inertial frame the whole time, the B observer is "in" two frames, one moving away from A and then towards A. The experience of A and B is not the same.

 

(It should be noted that speed is relative, but acceleration is absolute. We can actually "prove" that it's A who stayed home and B who "changed" frames. Just give them both a cup of coffee at the start of the experiment. It's B who spills their coffee, not A. But note it's not the acceleration that itself "causes" the difference in age of the twins, experiments can be designed with observers who don't change their own inertial frame but who pass clock readings to each other, and the same basic result arises. That can make it easier to understand, e.g. https://www.scienceforums.net/topic/104573-the-twin-paradox-and-other-variants/?do=findComment&comment=981200 )

 

 

[ To be fair, I'll point out I'm not going to engage in your gish gallop. This post is here for the person who stumbles on this thread in the mainstream science section of the forum. They need to know your views are not science. ]

 

 

You've said nothing here that I haven't said already.  For example, in post 28 I said:

 

SR apologists are also prone to point out that the situations of the two twins are "not symmetrical."  This is absolutely true, of course, but does nothing to answer the question posed.  Of course they are not symmetrical--one is moving (relative to the other) and one is not.  What the SR apologist does not, and cannot, explain or reconcile, is the concomitant claim that absolute motion cannot be detected.

 

Feynman said that the answer to the twin paradox is simple:  The one which has accelerated is the one who experiences time dilation, he says.  He's undeniably correct, because it is the one who has accelerated that is moving (relative to the one who has not).  And in SR (and every other theory which adopts the LT, for that matter) it is the moving clock which slows down.  Acceleration is universally admitted, even by SR, to be absolute, not relative, 

 

 

 

What part of anything I've said is "misrepresented" or "not science," pray-tell? Are you a player, or just another cheerleader?

Edited May 3, 2018 by Moronium

[Moronium]

Thanks for injecting some science. 

 

What people often seem to overlook is that the time dilation seen by observers in relative motion is balanced by length contraction, such that c can be the same for both observers, their relative motion notwithstanding. 

 

 

Yet another cheer-leader, eh?  "Reciprocal dilation" has now been shown to be non-existent.  Attempts to salvage it with solipsism are what can truly be said to be "psuedo-scientific," not the empirically established facts.

 

SR advocates are quite fond of saying "as seen by observers" as if reciprocal dilation is some visual empirical experience.  It isn't, and can't be.  As I've shown elsewhere, senses, standing alone, can never "tell" you which of two inertial  objects is moving.  That doesn't mean that there is simply "no truth" to the matter and that, as dictated by SR, each is motionless (notwithstanding the undeniable appearance of relative motion, which CAN be "seen").

 

Observers don't "see" reciprocal dilation.  They are told by SR  that they MUST assume it, that's all.  Even if they're wrong, like the travelling twin in the twin paradox.

 

If the travelling twin in the paradox has simply said:  "Ya know what?  I think I'm the one moving here, not my twin," then he would suddenly and magically "see" his earth twin's clock running faster than his own, not slower.  And he would have been right.  SR forbids him from doing this of course.  He must "see" what SR TELLS HIM to "see," nothing else.

Edited May 3, 2018 by Moronium

[Moronium]

 

While two observers are in relative motion, for both of them, the others' clocks is slow (while for both of them their own clock is perfectly normal). They must be, for the speed of light to be invariant.

 

(I know you don't like this - you think it's contradictory and illogical - but that's your own flawed interpretation, not standard well known science.)

 

 

 

1.  I don't disagree with the logic IF the conclusion is properly stated.  You say:  "They must be, for the speed of light to be invariant."  That is not accurate.  This would be accurate:  "They must be, for the speed of light to be measured to be invariant."   I've already dealt with this in detail in other threads (maybe this one too, I can't even remember anymore).  

 

Here's a repost from just one thread:

 

The speed of light cannot both "actually be" c and also be correctly measured to be c if the measuring instruments (clocks and rods) being used have "shrunk" or slowed down.  Experiments testing the LT have consistently shown, to an extremely high degree of accuracy, that the measuring instruments do in fact "shrink" and slow down in the prime (moving) frame in accordance with the LT equation. That can only mean one thing:  Although the speed of light is still "measured" to be c in the moving frame, it AINT c.

 

 

Edited May 3, 2018 by Moronium

[A-wal]

Of course that's not a paradox at all.  And that's also not the reason it's called a paradox.

 

Two people can have totally opposite "perceptions"  Nothing paradoxical about that at all.  It happens every day.  People make mistakes.

 

The "paradox" comes when SR tries to simultaneously claim that:

 

1.  There is no mistake at all.  Both are correct, but that

2.  Only one of the two twins is correct.

 

That's the "paradox," which SR "resolves" only by repudiating the first claim and affirming the second--which gives an absolute (frame independent) answer, not a relative one.

There's no paradox because SR doesn't say both 1 and 2 are true. Only 1 is true.

 

Try telling that to any knowledgeable theoretical physicist who has ever looked at the results of the H-K experiment.  Or, for that matter, anyone who has even a rudimentary familiarity with logic.

Any knowledgeable theoretical physicist who has ever looked at the results of the H-K experiment will understand that it supports, not refutes SR.

 

I have already explained in more detail why your assertion can't be true, as an objective matter, in another thread:

 

http://www.scienceforums.com/topic/31081-preferred-frame-geometry/?do=findComment&comment=355943  (post #3)

All you've done is show how you don;t understand the model. Stop claiming that as evidence that there's something wrong with the model!

 

Cheerleaders will get out at half-court and loudly chant:  "From the east to the west, we're the BEST!!" even if their team is down by 50 points at halftime in a basketball game.

 

That's understood.  That's their job. They are used for their enthusiasm, not for keeping or understanding the score. They aint no player, and they aint got no game.  No reason to expect any game from them.

I've explained to you time and again not only what SR describes also but why it must be an accurate description of reality. All you can do is repeat the same BS misunderstandings over and over and claim that it's the model's fault that it doesn't make sense to you.

 

Here's more elaboration on this general topic, once again imported from a pre-existing  thread where this post was originally made:

 

 

1.  SR starts with the reasonable-sounding proposition that, because the laws of physics are the same in all inertial frames, all such frames are 'equally valid."  It goes on to assert that, because they are "equally valid," you can randomly and arbitrarily pick "any old" inertial frame of reference from which to assess relative motion, and it will make no difference.  There is no reason to "prefer" any inertial frame over another.  OK, kinda sounds fair enough.  What next?

 

2.  In truth, it's all a "bait and switch" tactic that's being employed. In practice SR does not allow me to freely choose a frame of reference to calculate my relative motion from.  I MUST, instead, treat my own frame of reference as being absolutely motionless (like Lorentz' ether).  If I'm on a train, I cannot adopt the viewpoint that I am moving relative to the earth's surface.  I must insist that IT is moving, relative to me.  I am therefore, by strict mandate of SR's protocols, in a preferred frame which is not "freely chosen," but which is dictated by SR.  SR likes to assert that "you can never tell who's moving,"  but ironically this is all while undertaking to "inform" you about who's moving in every instance where you employ SR formulas (again, it's always all other objects in the universe which are outside of your reference frame--never you).

Utter nonsense! There is no frame that is independently moving in SR, all motion is relative. You keep making the claim that SR requires certain frames to be chosen above others, this is a misunderstanding of the most basic aspect of the model. You can't even grasp that but you think you understand enough to know that the model is wrong. Like I said, fcuking joke.

 

3.  Apart from being intuitively false as an empirical matter, this forced choice of a preferred frame presents other serious problems.  Once you move beyond just two objects, you end up with a infinite number of mandatory "preferred frames," i.e., one for each possible inertial frame.  This ends up in  implying such logical absurdities as asserting that each of two clocks (or every clock, of many) runs slower than the other(s), for example.  Because this is a self-refuting proposition, the theory cannot make empirically accurate predictions with respect to actual tangible objects in the objective physical world.

More nonsense. You can use as many moving clocks as you like with any relative velocities to any other clocks that you like and you'll get different rates of time for each clock depending on which frame you chose to use and all observers are correct, there's no contradiction and it doesn't matter which frame you use, any test will give the same results once any clocks are in the same frame as each other because all frames are equally valid.

 

So the original claim, i.e., that you could freely choose any inertial frame in SR, and still get the same results, is quickly shown to be a false promise and an invalid claim.

No, all you've quickly shown is that you're still unable to grasp the model.

 

Unfortunately shoddy sophistical tactics like these completely fool some people (like A-wal) who refuse to think critically about what they are being told.  Such people will then repeat the false claims, ad nauseum, and become more convinced that what they're saying is "true" with each repetition--at least so long as they are "preaching to choir," whose only response is to shout "Amen, Brother!"

Critical thinking only works if you can think well enough to understand the subject at hand. You clearly can't.

[Moronium]

Around 1907, Hermann Minkowski took Poincare's insight, and turned SR into a purely mathematical theory with no relation to phyical reality.

 

At the time, Einstein called Minkowski's treatment "superfluous over-learnedness" as I recall.  At one point he said (paraphrasing)  "Since the mathematicians have gotten involved, I don't understand special relativity myself."

 

Minkowski's mathematical trick, which smashed time and space together, had great appeal to mathematicians and his interpretation eventually came to prevail (for 30-40 years).

 

Under this interpretation, both time dilation and length contraction were said to be "illusory," a matter of misleading appearance, with no substance in reality.  This was, at least, a CONSISTENT view, for the reasons stated in my last post.  Problems developed for this "interpretation" later, however, when mu-meson experiments showed that time dilation was real, not illusory (these experiments did NOTHING to prove "reciprocal" dilation, of course.)

 

Physicists like Robertson, Bondi, and others therefore had to scramble to "reinterpret" SR in a manner that did not contradict the facts.  They had to settle for an interpretation which would be experimentally indistinguishable from a (correct) theory which posited absolute, not relative, simultaneity.  I have cited Robertson's research, later extended upon by Mansouri and Sexl, in other threads.  Here again is a brief excerpt from a wiki article summarizing their findings:

 

Mansouri and Sexl spoke about the "remarkable result that a theory maintaining absolute simultaneity is equivalent to special relativity." They also noticed the similarity between this test theory and Lorentz ether theory of Hendrik Lorentz, Joseph Larmor and Henri Poincaré. 

 

 

https://en.wikipedia.org/wiki/Test_theories_of_special_relativity

 

Like it or not, that's "actual science" not homespun pseudo-science concocted by shade-tree "relativists" who purport to know it all.

Edited May 3, 2018 by Moronium

[Moronium]

Rah, Rah, sis boom bah, A-wal.

 

As always, your "refutations" contain no substantive content at all.  They simply amount to a hollow, empty tautology which says:  If SR is true, then it is true.

 

But, actually, it's much worse than that.  You quickly omit the hypothetical "if" part and it becomes.

 

"SR is true in fact, therefore SR is true in fact."

 

This type of "reasoning" is tantamount to no reasoning whatsoever, in case ya aint heard.

[A-wal]

You continue to misrepresent the twins' paradox.

 

While two observers are in relative motion, for both of them, the others' clocks is slow (while for both of them their own clock is perfectly normal). They must be, for the speed of light to be invariant.

 

(I know you don't like this - you think it's contradictory and illogical - but that's your own flawed interpretation, not standard well known science.)

 

That reciprocal experience is what gives rise to the "paradox" in the "twins' paradox". In a scenario where A "stays home" and B zooms away from A then comes back to A, a learner can think "since at all times that they are in relative motion, the other's clock is always slower, how come B comes back and is actually younger"?

 

The answer is that the situation is not symmetrical. Observer A's clock stays in the same inertial frame the whole time, the B observer is "in" two frames, one moving away from A and then towards A. The experience of A and B is not the same.]

Exactly. He seems to be under the impression that because they end up in the same frame so you obviously have to use the measurements of that frame, it somehow invalidates the other frame's measurements.

 

Thanks for injecting some science. 

 

What people often seem to overlook is that the time dilation seen by observers in relative motion is balanced by length contraction, such that c can be the same for both observers, their relative motion notwithstanding. 

What? Time dilation is not balanced by length contraction, the two are cumulative, it's how the speed of light can be the same for both observers.

 

What do you mean "their relative motion not withstanding"? Time dilation combined with length contraction (velocity is distance over time) is what allows the speed of light to be constant in all inertial frames of reference despite their relative motion.

 

Yet another cheer-leader, eh?  "Reciprocal dilation" has now been shown to be non-existent.  Attempts to salvage it with solipsism are what can truly be said to be "psuedo-scientific," not the empirically established facts.

 

SR advocates are quite fond of saying "as seen by observers" as if reciprocal dilation is some visual empirical experience.  It isn't, and can't be.  As I've shown elsewhere, senses, standing alone, can never "tell" you which of two inertial  objects is moving.  That doesn't mean that there is simply "no truth" to the matter and that, as dictated by SR, each is motionless (notwithstanding the undeniable appearance of relative motion, which CAN be "seen").

 

Observers don't "see" reciprocal dilation.  They are told by SR  that they MUST assume it, that's all.  Even if they're wrong, like the travelling twin in the twin paradox.

 

If the travelling twin in the paradox has simply said:  "Ya know what?  I think I'm the one moving here, not my twin," then he would suddenly and magically "see" his earth twin's clock running faster than his own, not slower.  And he would have been right.  SR forbids him from doing this of course.  He must "see" what SR TELLS HIM to "see," nothing else.

Reciprocal time dilation is the only way to keep the speed of light constant. There's no possible way for one twin to be in absolute motion, they can only be in motion relative to each other.

 

1.  I don't disagree with the logic IF the conclusion is properly stated.  You say:  "They must be, for the speed of light to be invariant."  That is not accurate.  This would be accurate:  "They must be, for the speed of light to be measured to be invariant."   I've already dealt with this in detail in other threads (maybe this one too, I can't even remember anymore).  

 

Here's a repost from just one thread:

 

"The speed of light cannot both "actually be" c and also be correctly measured to be c if the measuring instruments (clocks and rods) being used have "shrunk" or slowed down.  Experiments testing the LT have consistently shown, to an extremely high degree of accuracy, that the measuring instruments do in fact "shrink" and slow down in the prime (moving) frame in accordance with the LT equation. That can only mean one thing:  Although the speed of light is still "measured" to be c in the moving frame, it AINT c."

And right here is why you're such a fcuking joke Moronium. Time dilation and length contraction is what allows the speed of light to be constant, and you're trying to use them to show that it isn't constant. :) You're obviously very confused.

[Moronium]

And right here is why you're such a fcuking joke Moronium. Time dilation and length contraction is what allows the speed of light to be constant, and you're trying to use them to show that it isn't constant. 

 

 

Wrong, yet again, A-wal.  TD and LC is what allows the speed of light to BE MEASURED TO BE constant, when it's actually not, that's all.

 

Being the abject solipsist that you are, you are naturally incapable of making any distinction between what a thing is measured to be, and what it actually is.  For you, there is nothing objective "out there."  There is no objective truth, independent of your mind.  Whatever ever you conclude (measure) simply must be what is.

Edited May 3, 2018 by Moronium

[A-wal]

Around 1907, Hermann Minkowski took Poincare's insight, and turned SR into a purely mathematical theory with no relation to phyical reality.

 

At the time, Einstein called Minkowski's treatment "superfluous over-learnedness" as I recall.  At one point he said (paraphrasing)  "Since the mathematicians have gotten involved, I don't understand special relativity myself."

 

Minkowski's mathematical trick, which smashed time and space together, had great appeal to mathematicians and his interpretation eventually came to prevail (for 30-40 years).

 

Under this interpretation, both time dilation and length contraction were said to be "illusory," a matter of misleading appearance, with no substance in reality.  This was, at least, a CONSISTENT view, for the reasons stated in my last post.  Problems developed for this "interpretation" later, however, when mu-meson experiments showed that time dilation was real, not illusory (these experiments did NOTHING to prove "reciprocal" dilation, of course.)

 

Physicists like Robertson, Bondi, and others therefore had to scramble to "reinterpret" SR in a manner that did not contradict the facts.  They had to settle for an interpretation which would be experimentally indistinguishable from a (correct) theory which posited absolute, not relative, simultaneity.  I have cited Robertson's research, later extended upon by Mansouri and Sexl, in other threads.  Here again is a brief excerpt from a wiki article summarizing their findings:

 

"Mansouri and Sexl spoke about the "remarkable result that a theory maintaining absolute simultaneity is equivalent to special relativity." They also noticed the similarity between this test theory and Lorentz ether theory of Hendrik Lorentz, Joseph Larmor and Henri Poincaré. "

 

https://en.wikipedia.org/wiki/Test_theories_of_special_relativity

 

Like it or not, that's "actual science" not homespun pseudo-science concocted by shade-tree "relativists" who purport to know it all.

Absolute simultaneity is easily shown to be false, events that are simultaneous in one frame can't be in another. I don't see how you can maintain absolute simultaneity without ignoring the consistency of the speed of light, how could that be equivalent to SR?

 

Rah, Rah, sis boom bah, A-wal.

 

As always, your "refutations" contain no substantive content at all.  They simply amount to a hollow, empty tautology which says:  If SR is true, then it is true.

 

But, actually, it's much worse than that.  You quickly omit the hypothetical "if" part and it becomes.

 

"SR is true in fact, therefore SR is true in fact."

 

This type of "reasoning" is tantamount to no reasoning whatsoever, in case ya aint heard.

If the postulates of SR are correct then the description that SR gives is the only one (or at least the simplest one) that self-consistently describes the nature of inertial motion.

[A-wal]

Wrong, yet again, A-wal.  TD and LC is what allows the speed of light to BE MEASURED TO BE constant, that's all.

 

Being the abject solipsist that you are, you are naturally incapable of making any distinction between what a thing is measured to be, and what it actually is.  For you, there is nothing objective "out there."  There is no objective truth, independent of your mind.  Whatever ever you conclude (measure) simply must be what is.

Measurements are how science is done. TD and LC are a requirement of a constant speed of light. It makes no sense to try to use to show that it isn't constant. This level of misunderstanding shows that you aren't worth anyone ones time. Stop posting in this thread. Seriously now, fcuk off!

Edited May 3, 2018 by A-wal

[Moronium]

Absolute simultaneity is easily shown to be false, events that are simultaneous in one frame can't be in another. I don't see how you can maintain absolute simultaneity without ignoring the consistency of the speed of light, how could that be equivalent to SR?

 

 

 

Why don't you review the extensive (3-part) publications of REAL scientists, like Sexl and Mansouri, if you really want to know "how they could be equivalent" rather than just bleating that they're not 24/7, eh?  Just a suggestion.

 

I have, on numerous occasions, probably in exchanges with you even, shown where the fallacy lies in this assertion:  

 

Absolute simultaneity is easily shown to be false, events that are simultaneous in one frame can't be in another.

 

 

I'm sure that, being incapable of critical thinking, you will never understand that absolute simultaneity can, indeed, be true, as even Einstein acknowledged (and all other reputable physicists). That's not their fault, it's yours.

Edited May 3, 2018 by Moronium

[A-wal]

Why don't you review the extensive (3-part) publications of REAL scientists, like Sexl and Mansouri if you really want to know "how they could be equivalent" rather than just bleating that they're not 24/7, eh?  Just a suggestion.

They must have used a variable speed of light.

 

I have, on numerous occasions, probably in exchanges with you even, shown where the fallacy lies in this assertion: 

Do you honestly believe that? :)

 

I'm sure that, being incapable of critical thinking, you will never understand that absolute simultaneously can, indeed, be true, as even Einstein acknowledged.  That's not their fault, it's yours.

Not if the speed of light is constant it can't be.

 

 

Edit: Damn typos.

Edited May 3, 2018 by A-wal

[Moronium]

On a hot day last summer, my five-year old nephew came to me and told me why things got hot.  He said, "I'll show you."

 

He took me out the the oil and chip road out front and said:  "See, there?  See that runny black stuff (he was pointing to the partially liquefied tar)?  That's what makes it hot!  Every time it comes out, it gets hot."

 

Like my nephew, some here seem to confuse effect with cause.

 

A-wal says, for example:

 

Reciprocal time dilation is the only way to keep the speed of light constant.

 

 

In addition to confusing epistemology with ontology, he appears to have it backwards.

 

Einstein first postulates (without any pretense of proof, which is proper) that the speed of light is constant.  Having made that pronouncement, he then finds it necessary to assert that time dilation must be treated as reciprocal in order for the math to work out right.  Reciprocal dilation does not "keep the speed of light constant," as though it's the cause of constancy.  It's the other way around.  If one asserts that light will be measured to be constant in all frames, AND that, Galileo's principle of relativity is true in all inertial frames, then he MUST posit reciprocal dilation.  Unfortunately, it is, as a matter of objective reality (as opposed to abstract mathematical theory), contradictory to make both claims.

 

SR can be seen as perfectly consistent, internally.  But the implications of it cannot be true "in reality."   Unfortunately, for those who can't distinguish logical validity from existential soundness, validity proves "truth."

 

Fraid not.

Edited May 3, 2018 by Moronium

[Moronium]

They must have used a variable speed of light.

 

 

 

Bingo!  Surprisingly, you're starting to wise up a little already, A-wal.

[A-wal]

On a hot day last summer, my five-year old nephew came to me and told me why things got hot.  He said, "I'll show you."

 

He took me out the the oil and chip road out front and said:  "See, there?  See that runny black stuff (he was pointing to the partially liquefied tar)?  That's what makes it hot!  Every time it comes out, it gets hot."

 

Like my nephew, some here seem to confuse effect with cause.

 

A-wal says, for example:

 

"Reciprocal time dilation is the only way to keep the speed of light constant."

 

In addition to confusing epistemology with ontology, he appears to have it backwards.

 

Einstein first postulates (without any pretense of proof, which is proper) that the speed of light is constant.  Having made that pronouncement, he then finds it necessary to assert that time dilation must be treated as reciprocal in order for the math to work out right.  Reciprocal dilation does not "keep the speed of light constant," as though it's the cause of constancy.  It's the other way around.  If one asserts that light will be measured to be constant in all frames, AND that, Galileo's principle of relativity is true in all inertial frames, then he MUST posit reciprocal dilation.  Unfortunately, it is, as a matter of objective reality (as opposed to abstract mathematical theory), contradictory to make both claims.

 

SR can be seen as perfectly consistent, internally.  But the implications of it cannot be true "in reality."   For those who can't distinguish logical validity from existential soundness, validity proves "truth."

It wasn't a comment of cause vs effect. Reciprocal time dilation (and length contraction) is the only way to keep the speed of light constant. It's the only way that observers that are in motion relative to each other can measure light moving at the same speed relative to themselves.

 

"They must have used a variable speed of light."

 

Bingo!  Surprisingly, you're starting to wise up a little already, A-wal.

I've always said that SR depends on the consistency of the speed of light, it's a description of how relative motion works with a constant velocity of light in every inertial frame. If the speed of light isn't constant then SR isn't wrong, it's just describing something else.

 

Nothing has ever shown that the speed of light varies between inertial frames but plenty has shown that it remains consistent in different inertial frames, SR is a model that describes observed reality and models that have a variable speed of light conflict with observed reality.

 

This is what it boils down to:

 

1. If two observers are inertially moving away from each other while shining a light at each other then the only way both observers can measure their own light moving away from them and the other object's light moving towards them at the same speed is if each is time dilated and length contracted from the other object's perspective.

 

2. If object 1 accelerates into object 2's frame then object 1 will have experienced less time on their watch than object 2 because object 1 was time dilated and length contracted from the perspective of this frame. If on the other hand object 2 accelerates into object 1's frame then object 2 will have experienced less time on their watch than object 1 because object 2 was time dilated and length contracted from the perspective of this frame.

 

3. This works in exactly the same way regardless of how many objects there are moving at different relative velocities or which frame they accelerate into. If a thousand objects that are all in motion relative to every other object all accelerate into the frame of reference of one of those objects then the amount of time that each one experienced on their own watch will be different, less than the elapsed time on the watch of the observer who was always in this frame and proportional to their previous velocity relative to this frame.